Process of producing hollow objects of plastic material.



P. SATTELKAU & H. DOMBRINK.

PROCESS OF PRODUCING HOLLOW OBJECTS OF PLASTIC MATERIAL.

APPLICATION FILED NOV. 3 I917.

Patented Dec. 17, 1918.

IN VENTORS 5A 7754 KA u H. DUMHEIIVK ICE.

PAUL SATTIQLKAU ANID HENRY DOMBRINK, OF OAKLAND, CALIFORNIA.

PROCESS PRODUCING HOLLOW OBJECTS OF PLASTIC MATERIAL.

Specification of Letters Patent.

Application filed November 3, 191 7. SerialNo. 200,051.

To all whom it may concern:

Be it known that we, PAUL SATTELKAU and HENRY DoMBRINK, citizens of the United States, residing at Oakland, in the county of Alameda, State of California,

have invented a new and useful Process of "Producinlg Hollow Objects of Plastic Material, of w in such full and clear terms as will enable those skilled in the art to construct and use the same.

This invention relates to a cement pipe and the process of manufacturing same, and

its object is to produce an exceedingly strong aand dense pipe capable of withstand ing co rable pressures without leakage.

An object of the invention is to produce a cement pipe which will contain the minimum of moisture at the time the cement sets as well as the minimum of interstitial spaces containing occluded air. I

In the drawing, there is illustrated a form of machine capable of producing the pipe by the process herein outlined.

While the term cement has been used herein for convenience in explanation, it will be understood that this pipe may be made of any plastic material capable of being handled in the manner of cement, and which will set quickly enough to make it commer cially valuable for the purposes herein disclosed. 3 7

Other objects of the invention will appear as the description proceeds.

An embodiment ofthe inventionis shown in the drawings in which the same reference numeral is applied to the same portion throughout, but we are aware that there may be modifications thereof.

Figure 1 is a side elevation of the complete apparatus,

'Fig. 2 is a vertical sectional view of the apparatus on the line 2-2, Fig. 1, looking in the direction of the arrows, and n Fig. 3 is an end view of a section of pipe having steel reinforcing therein.

The numeral 1 indicates a suitable journaled post, 2 is a similar post, which posts have removable bearing caps 3 and 4. The apparatus comprisesa tube formed of three sections 5, 6 and 7, each of which has flanges, as indicated at 8 to 12 inclusive, for securing the several parts of the tube together. Bolts 13, in such numbers as may be desired,

are used to connect the partsof the tube,

and, after being connected together, caps ch the following is a specification Patented Dec. 17, 1918.

14 and 15 are screwed on the ends of the segments forming the tube. The cap 15 has a trunnion 16 which rests in the bearingat the top of the post 1. The cap 14 has a hol low trunnion 17 which rests in the bearing at the top of the post 2. c

The shaft 17 has a pipe 18 inserted in the opening therethrough, and a valve 19 per-' mits the air to be exhausted from the tube formed by the segments 5 to? inclusive. A pulley 20 is mounted on the shaft 17, and it is driven at a high rate of speed from abelt V 21 leading to another pulley 22, which receives its power from any suitable source.

In order to prevent the tube from wabbling during the time the cement is being poured therein, the segments are provided with the circumferentially extending track 23, 24 and Y25, the latter parts making up a complete circle and resting upon bearing rollers 27, 28; the former carried in a bearing block 29, while the latter is carried in the lower portion of a post 30 which extendsabove the tube. This post has a movable arm 31 at its upper end, which arm carries a roller 32 bearing on the top ofthe ring surrounding the tube, and it may be removed from contact with said ring by releasing the pressure of a screw 36, which extends into the top of the post 30, said screw having an operating hand wheel 37.

The operation of manufacturing the pipe is as follows r A charge of the plastic material, of which the pipe is to be made in order to roduce a pipe of the desired thickness, i{ placed within the tubular member, the cap 5 being in place to prevent the escape of said ma terial from the tube. The cap 14 is then placed in position and the tube is mounted for rotation in the bearing 1 and 2. At that time or during the progress of the rotation of the tube, whatever air may be within the tube is withdrawn .therefrom through the pipe 18, whereupon the valve 19 is closed and the tube is rapidly rotated for such a length of time as experience determines is necessary to cause the plastic material to be evenly distributed throughout the length of the tube, and to set sufliciently to be selfsustaining. I

After the plastic material has assumed the position shown in Fig. 2, and has been rotated for such a length of time as is required to make it self-sustaining, the tube may be removed from its supports and set away for such a length of time as is necessary to permit the plastic material to harden enough to allow the removal of the segments 5 to 7 inclusive therefrom.

' It will be clear that a plastic material pipe, such as 39, in which no reinforcing is used, may be produced,'or a pipe such as the pipe 40 may be produced in which such an amount oi circumferential reinforcing 41 and longitudinal reinforcing 42 to at inclusive may be used as good practice and engineering requires or demands for the particular pipe to be made.

It will be clear to those skilled in the art that by increasing the vacuum Within the mold to the highest practicable point that any bubbles of air contained Within the mass of plastic material Will be completely removed therefrom and the plastic material Will, by reason of such removal of air bubbles, solidify much denser than would be the case if such bubbles were allowed to remain therein.

Having thus described our invention What We claim as new and'desire to secure by Letters Patent of the United States is as folloWs, express reservations being made of permissible modifications.

A process of producing hollow objects from plastic material which consists in charging a receptacle With a quantity of plastic material, reducing the air pressure Within the receptacle below atmospheric, rapidly rotating the receptacle, until the plastic material therein forms a shell on the inside of the cylinder, continuing the rotation until the material has set sufiiciently to be self-sustaining, discontinuing the rotation, and then removing the receptacle fro the hollow object produced.

In testimony whereof We have hereunto set our hands this 8th day of @ctober A. D, 191?, I

- PAUL SATlELKAU HENRY DQMBRINK. 

